Drug Detail:Flumazenil (Flumazenil [ floo-maz-e-nil ])
Drug Class: Antidotes
Romazicon - Clinical Pharmacology
Flumazenil, an imidazobenzodiazepine derivative, antagonizes the actions of benzodiazepines on the central nervous system. Flumazenil competitively inhibits the activity at the benzodiazepine recognition site on the GABA/benzodiazepine receptor complex. Flumazenil is a weak partial agonist in some animal models of activity, but has little or no agonist activity in man.
Flumazenil does not antagonize the central nervous system effects of drugs affecting GABA-ergic neurons by means other than the benzodiazepine receptor (including ethanol, barbiturates, or general anesthetics) and does not reverse the effects of opioids.
In animals pretreated with high doses of benzodiazepines over several weeks, ROMAZICON elicited symptoms of benzodiazepine withdrawal, including seizures. A similar effect was seen in adult human subjects.
Pharmacokinetics
After IV administration, plasma concentrations of flumazenil follow a two-exponential decay model. The pharmacokinetics of flumazenil are dose-proportional up to 100 mg.
Special Populations
Pharmacokinetics in Pediatric Patients
The pharmacokinetics of flumazenil have been evaluated in 29 pediatric patients ranging in age from 1 to 17 years who had undergone minor surgical procedures. The average doses administered were 0.53 mg (0.044 mg/kg) in patients aged 1 to 5 years, 0.63 mg (0.020 mg/kg) in patients aged 6 to 12 years, and 0.8 mg (0.014 mg/kg) in patients aged 13 to 17 years. Compared to adults, the elimination half-life in pediatric patients was more variable, averaging 40 minutes (range: 20 to 75 minutes). Clearance and volume of distribution, normalized for body weight, were in the same range as those seen in adults, although more variability was seen in the pediatric patients.
Contraindications
ROMAZICON is contraindicated:
- in patients with a known hypersensitivity to flumazenil or benzodiazepines.
- in patients who have been given a benzodiazepine for control of a potentially life-threatening condition (eg, control of intracranial pressure or status epilepticus).
- in patients who are showing signs of serious cyclic antidepressant overdose (see WARNINGS).
Precautions
Use in Drug- and Alcohol-Dependent Patients
ROMAZICON should be used with caution in patients with alcoholism and other drug dependencies due to the increased frequency of benzodiazepine tolerance and dependence observed in these patient populations.
ROMAZICON is not recommended either as a treatment for benzodiazepine dependence or for the management of protracted benzodiazepine abstinence syndromes, as such use has not been studied.
The administration of flumazenil can precipitate benzodiazepine withdrawal in animals and man. This has been seen in healthy volunteers treated with therapeutic doses of oral lorazepam for up to 2 weeks who exhibited effects such as hot flushes, agitation and tremor when treated with cumulative doses of up to 3 mg doses of flumazenil.
Similar adverse experiences suggestive of flumazenil precipitation of benzodiazepine withdrawal have occurred in some adult patients in clinical trials. Such patients had a short-lived syndrome characterized by dizziness, mild confusion, emotional lability, agitation (with signs and symptoms of anxiety), and mild sensory distortions. This response was dose-related, most common at doses above 1 mg, rarely required treatment other than reassurance and was usually short lived. When required, these patients (5 to 10 cases) were successfully treated with usual doses of a barbiturate, a benzodiazepine, or other sedative drug.
Practitioners should assume that flumazenil administration may trigger dose-dependent withdrawal syndromes in patients with established physical dependence on benzodiazepines and may complicate the management of withdrawal syndromes for alcohol, barbiturates and cross-tolerant sedatives.
Pediatric Use
The safety and effectiveness of ROMAZICON have been established in pediatric patients 1 year of age and older. Use of ROMAZICON in this age group is supported by evidence from adequate and well-controlled studies of ROMAZICON in adults with additional data from uncontrolled pediatric studies including one open-label trial.
The use of ROMAZICON to reverse the effects of benzodiazepines used for conscious sedation was evaluated in one uncontrolled clinical trial involving 107 pediatric patients between the ages of 1 and 17 years. At the doses used, ROMAZICON's safety was established in this population. Patients received up to 5 injections of 0.01 mg/kg flumazenil up to a maximum total dose of 1.0 mg at a rate not exceeding 0.2 mg/min.
Of 60 patients who were fully alert at 10 minutes, 7 experienced resedation. Resedation occurred between 19 and 50 minutes after the start of ROMAZICON administration. None of the patients experienced a return to the baseline level of sedation. All 7 patients were between the ages of 1 and 5 years. The types and frequency of adverse events noted in these pediatric patients were similar to those previously documented in clinical trials with ROMAZICON to reverse conscious sedation in adults. No patient experienced a serious adverse event attributable to flumazenil.
The safety and efficacy of ROMAZICON in the reversal of conscious sedation in pediatric patients below the age of 1 year have not been established (see CLINICAL PHARMACOLOGY: Pharmacokinetics in Pediatric Patients).
The safety and efficacy of ROMAZICON have not been established in pediatric patients for reversal of the sedative effects of benzodiazepines used for induction of general anesthesia, for the management of overdose, or for the resuscitation of the newborn, as no well-controlled clinical studies have been performed to determine the risks, benefits and dosages to be used. However, published anecdotal reports discussing the use of ROMAZICON in pediatric patients for these indications have reported similar safety profiles and dosing guidelines to those described for the reversal of conscious sedation.
The risks identified in the adult population with ROMAZICON use also apply to pediatric patients. Therefore, consult the CONTRAINDICATIONS, WARNINGS, PRECAUTIONS, and ADVERSE REACTIONS sections when using ROMAZICON in pediatric patients.
Romazicon Dosage and Administration
ROMAZICON is recommended for intravenous use only. It is compatible with 5% dextrose in water, lactated Ringer's and normal saline solutions. If ROMAZICON is drawn into a syringe or mixed with any of these solutions, it should be discarded after 24 hours. For optimum sterility, ROMAZICON should remain in the vial until just before use. As with all parenteral drug products, ROMAZICON should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.
To minimize the likelihood of pain at the injection site, ROMAZICON should be administered through a freely running intravenous infusion into a large vein.
ROMAZICON
flumazenil injection, solution |
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ROMAZICON
flumazenil injection, solution |
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Labeler - Genentech, Inc. (080129000) |
Establishment | |||
Name | Address | ID/FEI | Business Operations |
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F. Hoffmann-La Roche Ltd | 482242971 | ANALYSIS(0004-6911, 0004-6912) , API MANUFACTURE(0004-6911, 0004-6912) , MANUFACTURE(0004-6911, 0004-6912) |
Establishment | |||
Name | Address | ID/FEI | Business Operations |
---|---|---|---|
F. Hoffmann-La Roche Ltd | 485244961 | MANUFACTURE(0004-6911, 0004-6912) , PACK(0004-6911, 0004-6912) , LABEL(0004-6911, 0004-6912) |